Holy Fire used to be a holy talent before it was trainable. Make it the Holy specialization spell!
I think it should be changed to have a damage/healing component like Penance, so if you cast it on a friendly target, it heals and leaves a HoT on them.
It has a long cooldown so it can be beefier than a flash heal.

Helps with leveling, and I would think Disc leveling would want to stick with Smite for Evangelism anyway.
Actually, Disc gains Penance for leveling at 10 instead of 60, so this can be the tradeoff.

The new Holy level 10 spell is pretty simple, but it also has a lot of play with Chakra. I am just pointing this out, because many players never noticed the talent that made the old Holy level 10 (Desperate Prayer) into a tool that could heal others.